Massachusetts Plumbers Journeyman Practice Exam

The recommended thickness for concrete walls in the construction of sumps and tanks designed to hold sewage is generally around 3 inches. This thickness provides a balance between structural integrity and weight, ensuring that the tank can withstand the pressure exerted by the sewage inside. Additionally, a thickness of 3 inches helps protect against potential leaks and reinforces the overall durability of the tank or sump in various environmental conditions.

Thinner walls, such as 1 inch or 2 inches, may not provide the necessary strength or durability to accommodate the weight and pressure of the sewage, increasing the risk of structural failure. While 4 inches may seem like a robust option, that could be unnecessarily heavy and more costly than required for typical applications, potentially leading to inefficient usage of materials. Therefore, 3 inches is often considered the optimal standard in practice.